"Is the boy in the study?" is how you would ask if a boy is in the room specifically designated as a study or home office in Engpsh.

This question is formed using the verb "to be" (in this case, "is") and the preposition "in," which is used to indicate location. "The boy" is the subject of the sentence and "the study" is the location.

Here are some additional examples of how the preposition "in" can be used to indicate location in Engpsh:

The cat is in the kitchen. (猫在厨房里。)
The book is on the table. (书在桌子上。)
The pencil is under the desk. (铅笔在桌子下面。)
The dog is outside. (狗在外面。)